You can have a two column foreign key. create table employee (id int primary key not null, company_id int not null, supervisor_id int); alter table employee add unique (id, company_id); alter table employee add foreign key (supervisor_id, company_id) references employee (id, company_id); Jon > -----Original Message----- > From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general- > owner@xxxxxxxxxxxxxx] On Behalf Of Matthew Wilson > Sent: Monday, April 14, 2008 12:36 PM > To: pgsql-general@xxxxxxxxxxxxxx > Subject: [GENERAL] How do I make sure that an employee and supervisor > belong to the same company? > > I have an employees table and one column in the employees table is > "supervisor_id" which is an FK to the id column. > > I have employees from numerous companies all in the same table. I have > a column called company_id that indicates the company. > > I want to make sure that an employee chooses a supervisor from the same > company. I have a column called company_ID. How do I make sure that > the employee company ID matches the supervisor's company ID? > > Do I need to use a trigger or is there a way I can do this with foreign > keys? > > TIA > > Matt > > > -- > Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general
